Monday, March 3, 2008

They’ve saved your life more than once, but they don’t require thanks. They weigh the same as you and move the way you do, but they don’t breathe. They get in car crashes over and over again and they don’t seem to mind. What could we possibly be talking about? Crash test dummies!

Crash test dummies first arrived on the scene in 1949 for the U.S. Air Force. The Air Force needed a way to test ejection seats from airplanes, but the technology was getting so sophisticated that it became dangerous to continue using human volunteers. They needed something that would simulate human reactions without using live human beings. The name of their first test dummy was Sierra Sam.

Between the time of Sierra Sam’s invention in 1949 and 1966, there was no set standard in dummies that were being produced. They were all different which made it very difficult to collect reliable data. They were also only being used to test airplane ejection seats and airplane seatbelts. In 1966 a new dummy was produced that was specifically made to test automobiles. This revolutionized the car manufacturing industry because they could now begin to test the effects of crashes on the human body. General Motors became the leader in crash test dummy technology by producing Hybrid I, Hybrid II and in 1997 Hybrid III. With each new model, the data has gotten consistently better. All dummies take on the human form in weight, size and proportion. There are many different sizes as there are many different sized people. They have spines made out of metal discs and rubber padding, necks that move, a steel rib cage and knees that respond to impact like a human knee would. On top of these traits, the Hybrid III also has vinyl skin with electronic sensors which measure the forces that different body parts can experience during a crash.

Before a dummy is placed in a car, they are given outfits to wear. This is no fashion statement though. Wearing clothes allows them to slide on the car seat as a human might. When a dummy is placed in a car, researchers apply paint to various body parts. Different colors are used for different areas of the body. This way, when the researcher crashes the car, they can then look at the amount of paint that transfers from the dummy’s body to parts of the car. If, for instance, red paint is placed on the dummy’s knee and after the crash there is a lot of red paint on the steering wheel, the researcher knows that the placement of the steering wheel should be adjusted in order to prevent knee injuries.

Researchers also collect data from sensors that are placed inside the dummy. There are three different kinds of sensors; accelerometers, load sensors and motion sensors. Accelerometers measure how fast a body part moves upon impact. For instance, if you hit something hard, like a brick wall, your head will move very quickly, but if you hit something soft like a pillow, it will move more slowly because the impact is absorbed. Accelerometers are placed inside the dummy’s head, chest, pelvis, legs and feet. Load sensors measure how much force is being placed on the body of the dummy upon impact. This measure of force can be used to determine how much load a bone can take before it breaks. The movement sensors are placed in a dummy’s chest. This measures how much the chest can deflect. In other words, it can tell the researcher how much the chest can be pushed in without causing life-threatening injuries.

By analyzing the collected data after a crash, researchers can scientifically determine what parts of the car can be considered safe and what parts need improvement. Because of these highly sophisticated tests, the automobiles we drive are much safer than they used to be.

So, think twice the next time you decide to call someone a dummy, you will actually be giving them a compliment!